This invention pertains to an epoxy useful, for example, as a coating for aircraft carrier decks.
It is important that many surfaces are made of a non-skid coating. For instance, it is desirable that the deck of an aircraft carrier be made of a non-skid surface. It is also desirable that such surfaces be durable. This is particularly true for the portion of the deck where the aircraft take off and land, which is exposed to severe wear. Currently, the aircraft decks are made using solvent-based epoxy coatings, which are applied so as to form ridges.
The present inventors have recognized, however, that there exists a need for a more durable coating, and a coating made without solvents. The present inventors have also recognized that a coating lacking volatile solvents would be desirable so as to avoid use of solvents that can be hazardous, and which must be evaporated off to provide the final coating.
This invention solves one or more of the problems and disadvantages described above.
In one broad respect, this invention is a process useful for providing a coating for a solid surface, comprising: applying a primer onto the solid surface to form a primer coating, wherein the primer is prepared from an amine curing agent, a polysulfide toughening agent, an epoxy resin, a rubber toughening agent, a fire retardant, a glass fiber thixotrope, and a pigment; applying a topcoat onto the primer coating, wherein the topcoat is prepared from an amine curing agent, a polysulfide toughening agent, an epoxy resin, a rubber toughening agent, a fire retardant, a glass fiber thixotrope, a pigment, and an abrasive aggregate. As used herein, xe2x80x9ccoatingxe2x80x9d may refer to either the primer, the topcoat, a generic mixture formed from the components described herein, or combinations thereof.
In general, a coating of this invention may be prepared from (formulated from), independently in each occurrence, about 20 to about 60 percent of the amine curing agent; about 0.01 to about 30 percent of the polysulfide toughening agent; about 0.01 to about 15 percent based on the total weight of the coating of the corrosion inhibitor; about 0.01 to about 10 percent based on the total weight of the coating of the glass fiber; about 0.01 to about 3 percent based on the total weight of the coating of an moisture penetration inhibitor; about 0.01 to about 35 percent based on the total weight of the coating of the fire retardant; about 10 to about 90 percent based on the total weight of the coating of the epoxy resin; 4 to about 40 percent based on the total weight of the coating of the rubber toughening agent; about 0.01 to about 30 percent based on the total weight of the coating of the pigment about 0.01 to about 10 percent based on the total weight of the coating of the ultraviolet light stabilizer; and/or about 0.01 to about 45 percent based on the total weight of the coating of the abrasive aggregate.
In one broad respect, this invention is a process useful for providing a coating for a solid surface, comprising: applying a primer onto the solid surface to form a primer coating on the surface, wherein the primer is prepared from a first amine side which comprises a mixture of an amine curing agent, a toughening agent, at least one corrosion inhibitor, a moisture penetration inhibitor, a fire retardant, and a glass fiber thixotrope a first epoxy side which comprises a mixture of: an epoxy resin, a toughening agent, at least one corrosion inhibitor, a moisture penetration inhibitor, a darkening pigment, and a glass fiber thixotrope applying a topcoat onto the primer coating, wherein the topcoat is prepared from a second amine side which comprises a mixture of: an amine curing agent, a toughening agent, an ultraviolet light absorber and stabilizer, a fire retardant, an infrared light reflecting pigment, a glass fiber thixotrope and impact toughening agent, and an abrasive aggregate, and a second epoxy side which comprises a mixture of: an epoxy resin, a toughening agent, a glass fiber thixotrope and impact toughening agent, an ultraviolet light absorber and stabilizer, and an abrasive aggregate.
In one embodiment, the first amine side comprises about 40 to about 60 percent of the amine curing agent, about 10 to about 30 percent of the toughening agent, about 0.01 to about 6 percent of at least one corrosion inhibitor, about 0.01 to about 5 percent of the glass fiber, about 0.01 to about 3 percent of the moisture penetration inhibitor, and/or about 10 to about 35 percent of the fire retardant.
In one embodiment, the first epoxy side comprises about 50 to about 90 percent of the epoxy resin, about 10 to about 40 percent of the toughening agent, about 0.01 to about 6 percent of the corrosion inhibitor, about 0.01 to about 15 percent of the pigment, and/or about 0.01 to about 2 percent of the glass fiber.
In one embodiment, the second amine comprises about 25 to about 50 percent of the amine curing agent, about 0.01 to about 10 percent of the toughening agent, about 0.01 to about 6 percent of the corrosion inhibitor, about 15 to about 25 percent of the pigment, about 0.01 to about 45 percent of the abrasive aggregate, about 0.01 to about-5 percent of the glass fiber, and/or about 5 to about 15 percent of the fire retardant.
In one embodiment, the second epoxy side comprises about 20 to about 45 percent of the epoxy resin, about 8 to about 20 percent of the toughening agent, about 0.01 to about 6 percent of the corrosion inhibitor, about 0.01 to about 10 percent of the ultraviolet light stabilizer, about 0.01 to about 15 percent of the pigment, and/or about 0.01 to about 5 percent of the glass fiber.
In another broad respect, this invention is an epoxy topcoat comprising a cured mixture that is formulated from an epoxy resin, a polysulfide toughening agent, optionally, an ultraviolet light stabilizer, a pigment, a glass fiber thixotrope, an abrasive aggregate, a fire retardant, an amine curing agent, and a rubber toughening agent.
In another broad respect, this invention is an epoxy primer comprising a cured mixture that is made from an amine curing agent, a polysulfide toughening agent, a fire retardant, a glass fiber thixotrope an epoxy resin, a rubber toughening agent, a pigment, optionally, a corrosion inhibitor, and optionally, a moisture penetration inhibitor.
In another broad respect, this invention is a process useful for providing a coating for a solid surface, comprising: applying a coating onto the solid surface, wherein the coating is prepared from an amine side which comprises a mixture of: an amine curing agent, a polysulfide toughening agent; and an epoxy side which comprises a mixture of: an epoxy resin, a rubber toughening agent, and wherein the coating is also prepared from a fire retardant, a glass fiber thixotrope, a pigment, and an abrasive aggregate, and wherein the surface may be primed or un-primed prior to application of the topcoat.
The primer is used to promote adhesion of the non-skid topcoat and to inhibit corrosion of a metal substrate to which the primer may be applied. Either or both of the primer sides may include an ultraviolet light absorber and stabilizer. In one embodiment, the second amine side or the second epoxy side or both may include a pigment, such as a darkening pigment. In one embodiment the epoxy side and amine side include different pigments (e.g., one is white and one is black) to assist the user in achieving adequate mixing of the two sides.
In one embodiment, the topcoat is applied in a manner such that a plurality of ridges are formed by the topcoat such as by rolling, trowelling, raking or spraying. The rolling can be through use of a phenolic napless roller of a design such that upon application, ridges and valleys are formed to supply additional slip resistance. For many applications, the topcoat may be applied using one gallon of topcoat for every 20-30 square feet of surface to be coated. The topcoat may be applied to the primer as soon as the primer is cured to a tack free state. Typically, the topcoat is tack free within 1 to 48 hours after being applied, depending on temperature and other conditions. In general, hotter ambient temperatures lead to shorter tack free times.
In another broad respect, this invention is a method of manufacturing an epoxy side and an amine side for use in the formation of a coating, comprising: forming a mixture of an amine side from an amine curing agent and a polysulfide toughening agent, forming a mixture of an epoxy side from an epoxy resin and a rubber toughening agent, wherein the amine side is also formed from a fire retardant, a glass fiber thixotrope, a pigment, an abrasive aggregate, a moisture penetration inhibitor, an ultraviolet light stabilizer, or combination thereof, and wherein the epoxy side is also formed from a fire retardant, a glass fiber thixotrope, a pigment, an abrasive aggregate, a moisture penetration inhibitor, an ultraviolet light stabilizer, or combination thereof.
In another broad respect, this invention is a process useful for providing a coating for a solid surface, comprising: applying a coating onto the solid surface, wherein the coating is prepared from (a) an amine curing agent, (b) a polysulfide toughening agent, (c) an epoxy resin, (d) a rubber toughening agent, and (e) a fire retardant, a glass fiber thixotrope, a pigment, a corrosion inhibitor, a moisture penetration inhibitor, an ultraviolet light stabilizer, an abrasive aggregate, or a combination thereof.
The surfaces to be coated may include metal surfaces such as but not limited to the deck of a ship, including the deck of an aircraft carrier, the surface of an oil well drilling platform, and other industrial or utility thoroughfares.
The composition may include at least one moisture penetration inhibitor in the first amine side and at least one moisture penetration inhibitor in the first epoxy side. In one embodiment, the primer is white and the epoxy side is black (or vice versa) so that when mixed, a gray color is created. This is advantageous for purposes of handling, mixing, and application of the materials.
In one aspect, the toughening agent may be a rubber toughening agent or a polysulfide toughening agent.
In one respect, the abrasive aggregate is comprised of a mixture of coarse aluminum powder and aluminum pellets.
In another respect, this invention is a coating composite formed by application of a topcoat layer to a primer layer. The topcoat and primer may be made from the epoxy and amine sides described herein. The laminate can thus be described as a composition comprising a topcoat layer adhered or bonded to a primer layer.
In another broad respect, this invention is a process useful for making a non-skid coating kit, comprising a first amine side and first epoxy side of a primer and a second amine side and a second epoxy side of a topcoat, wherein the process comprises: (a) combining an amine curing agent, a toughening agent, a corrosion inhibitor, and fire retardant to form the first amine side; adding the first amine side to a first container and then sealing the container; (b) combining an epoxy resin, a toughening agent, a corrosion inhibitor, an ultraviolet light stabilizer, a pigment, and a thixotrope glass fiber reinforcing agent to form the first epoxy side; adding the first epoxy side to a second container and then sealing the container; (c) combining an amine curing agent, a rubber toughening agent, a corrosion inhibitor, an ultraviolet light reflector, a fire retardant, a thixotrope glass fiber reinforcing agent to form the second amine side to a container and then sealing the container; and (d) combining an epoxy resin, a toughening agent, a pigment, a thixotrope glass fiber reinforcing agent, an ultraviolet light absorber and stabilizer, and an aggregate to form the second epoxy side; adding the second epoxy side to a second container and then sealing the container.
This invention thus provides a coating useful for applications such as but not limited to the deck of an aircraft carrier. Advantageously, the coating may be made from 100% solids components obtained from a supplier without further dilution, i.e., without the addition of volatile solvents. As used herein, a solvent such as water or an organic compound refers to materials that dissolves the epoxy resin and/or amine starting materials, and which evaporates from the coating upon application and/or exposure to an open environment (such as to air). Representative examples of such volatile organic solvents that may be advantageously absent from the components used to make the final coating include low molecular weight halogenated hydrocarbons such as chloroform and carbon tetrachloride, hydrocarbons, alcohols, ketones, ethers, glycol ethers, and so forth. In the practice of this invention, the starting materials and final cured coating are substantially free of solvents, containing at most only minor amounts of such solvents and no more than about 40 percent of the component weight. Advantageously, the coating has excellent durability and has improved durability relative to the solvent-based coatings currently in use.
The type of substrates and surfaces on which the coating of this invention may be used vary widely. For example, the type of surfaces that can be treated with the coating of this invention includes glass, ceramics, metals, and plastics. Typically, the surface is metal.
The final cured coating of this invention has a thickness which can vary widely depending on the end use. In general, the coating has a thickness of from about 0.1 cm to about 2 cm, though thicknesses above and below these thicknesses are anticipated.
The epoxy resin used in the practice of this invention may vary and includes conventional, commercially available epoxy resins. Two or more epoxy resins may be employed in combination. In general, the epoxy resins can be glycidated resins, cycloaliphhatic resins, epoxidized oils, and so forth. The glycidated resins are frequently the reaction product of a glycidyl ether, such as epichlorohydrin, and a bisphenol compound such as bisphenol A. C4-C28 alkyl glycidyl ethers; C2-C28 alkyl-and alkenyl-glycidyl esters; C1-C28 alkyl-, mono- and poly-phenol glycidyl ethers; polyglycidyl ethers of pyrocatechol, resorcinol, hydroquinone, 4,4xe2x80x2-dihydroxydiphenyl methane (or bisphenol F), 4,4xe2x80x2-dihydroxy-3,3xe2x80x2-dimethyldiphenyl methane, 4,4xe2x80x2-dihydroxydiphenyl dimethyl methane (or bisphenol A), 4,4xe2x80x2-dihydroxydiphenyl methyl methane, 4,4xe2x80x2-dihydroxydiphenyl cyclohexane, 4,4xe2x80x2-dihydroxy-3,3xe2x80x2-dimethyldiphenyl propane, 4,4xe2x80x2-dihydroxydiphenyl suflone, and tris (4-hydroxyphynyl)methane; polyglycidyl ethers of the chlorination and bromination products of the above-mentioned diphenols; polyglycidyl ethers of novolacs; polyglycidyl ethers of diphenols obtained by esterifying ethers of diphenols obtained by esterifying salts of an aromatic hydrocarboxylic acid with a dihaloalkane or dihalogen dialkyl ether; polyglycidyl ethers of polyphenols obtained by condensing phenols and long-chain halogen paraffins containing at least two halogen atoms; N,Nxe2x80x2-diglycidyl-aniline; N,Nxe2x80x2-dimethyl-N,Nxe2x80x2-diglycidyl-4,4xe2x80x2-diaminodiphenyl methane; N,N,Nxe2x80x2,Nxe2x80x2-tetraglycidyl-4,4xe2x80x2-diaminodiphenyl methane; N,Nxe2x80x2-diglycidyl-4-aminophenyl glycidyl ether; N,N,Nxe2x80x2,Nxe2x80x2-tetraglycidyl-1,3-propylene bis-4-aminobenzoate; phenol novolac epoxy resin; cresol novolac epoxy resin; and combinations thereof. Representative non-limiting examples of epoxy resins useful in this invention include bis-4,4xe2x80x2-(1-methylethylidene) phenol diglycidyl ether and (chloromethyl) oxirane Bisphenol A diglycidyl ether. Commercially available epoxy resins that can be used in the practice of this invention include but are not limited to arildite GY6010 and Epon 828. The epoxy resin can be used in any amount effective to form a coating of this invention. In general, the amount of epoxy resin used in the first epoxy side for the primer is from about 50 to about 90 percent by weight, and from about 20 to about 45 percent in the second epoxy side for topcoat. The epoxy resin is thinner than the type of resin used to make solvent-based epoxy coatings. Typically, the epoxy resin has a viscosity of from about 11,000 to about 14,000.
The toughening agent used in the practice of this invention provides toughening and durability characteristics to the coating. By toughening it is meant that the material has imparted to it a greater impact strength. The toughening agent may be selected from conventional toughening agents such as rubber toughening agents and polysulfide toughening agents. The toughening agent can vary. The polysulfide toughening agent may be an epoxy terminated polysulfide polymer. One representative formula for such materials is: 
where n may be from 1 to 1,000. It is believed that the polysulfide toughening agent reacts during the epoxy curing to the amine function of the curing agent. Such compounds are well known, and are currently available commercially under the tradename ELP-3, sold by Rohm and Haas. The polysulfide toughening agent is epoxy terminated and can react with the amine curing agent, but is stable in the epoxy resin. A toughening agent functions to improve impact resistance. Toughening agents function by forming a secondary phase within the polymer matrix. This secondary phase is rubbery and hence is capable of crack growth arrestment. This crack arresting function provides improved impact toughness.
A representative example of a rubber toughening agents includes amine-terminated butadiene nitrile (ATBN) and carboxy-terminated butadiene nitrile (CTBN). ATBN is amine terminated so that it can react with the epoxy functionality and is stable upon mixture with an amine curing agent. A representative example of a polysulfide toughening agent is an epoxy- terminated polysulfide toughening agent. The ability of ATBN or the polysulfide toughening agent to react with their resin complements allows for good chemical bonding between separate phases (rubber and resin).
The abrasive aggregate may be selected from a wide variety of materials. The abrasives are employed in amounts effective to-provide additional anti-skid properties to the coating. Representative examples of such abrasives include metals such as aluminum, pumice, garnet, silica, ceramic fibers or whiskers such as of magnesium oxide, aluminum nitride, boron nitride, zinc oxide, aluminum oxide, quartz, polymer, rubber, and combinations thereof. The aggregate is employed in a wide range of amounts. In general, the aggregate is used in an amount of from about 20 to about 50 percent by weight of the second amine side, and from about 25 to about 60 percent of second epoxy side. The aggregate serves to provide filler material and an abrasive surface.
The coating of this invention includes a glass fiber, which provides both thixotropic rheology modification as well as an impact toughening agent. Such glass fibers include those having an average fiber diameter of about 0.2 to about 5 microns and a surface area as measured by BET of about 0.01 to about 25 meters squared per gram (m2/g). In one embodiment, the BET is about 0.3 to about 6.25 m2/g. In the first amine side, the amount of glass fiber may be from about 0.01 to about 5 percent; from about 0.01 to about 2 percent for the first epoxy side; from about 0.01 to about 5 percent for the second amine side, and from about 0.01 to about 5 percent for the second epoxy side.
For the primers, one or more corrosion inhibitors may be included. These serve to reduce the amount of corrosion of a metal substrate at the primer/surface interface. A wide variety of such corrosion inhibitors may be used. Representative examples of such corrosion inhibitors include zinc-based inhibitors such as zinc phosphate, zinc-5-nitro-isophthalate, zinc molybdate, and zinc oxide and hydrophobic, moisture penetration inhibitors such as hydrophobic, amorphous fumed silica. These may be used in any amount effective to provide corrosion inhibition.
In the practice of this invention, a UV light stabilizer may be included. This serves to protect the cured coating from the harmful effects of UV light. Representative examples of such stabilizers include sterically hindered piperidine derivatives including an alkyl substituted hydroxy piperidines such as dimethyl sebacate, methyl-1,2,2,6,6-pentamethyl-4-piperidinyl sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, and 1,2,2,6,6-pentamethyl-4-piperidinol. This may be used in any amount effective to provide UV stabilization.
The coating can include one or more pigments to provide any desired color. The pigments can vary, depending on the desired color of the final coating. For example, if a gray coating is desired, white and black pigments can be used. If a yellow coating is desired, then yellow pigments can be employed, and so on. A representative example of a darkening pigment is black iron oxide. Black iron oxide also has the desirable property of being infrared transparent and thus may serve as an IR transparent darkening agent. This is beneficial because infrared absorption by the coating causes the surface temperature to rise, which is undesirable. Likewise, an IR reflector may be included in the coatings of this invention. One such IR reflector is titanium dioxide, which may also serve as a pigment. By reflecting IR light, the coating is less prone to becoming heated in sunlight.
Various fire retardants may be used in the practice of this invention. Common fire retardants include an alumina such as alumina trihydrate, magnesium hydroxide, bismuth oxide, zinc borate, potassium tripolyphosphate, and antimony oxide. Combinations of these fire retardants can be employed, such as magnesium hydroxide with alumna trihydrate, and zinc borate with magnesium hydroxide and/or alumna trihydrate. Fire retardants that are not a known carcinogens are preferred in the practice of this invention. In general, the fire retardants may be employed in an amount of from about 5 to about 40 percent by weight based on the total weight of a given formulation.
On the amine side of the primer and topcoat, an amine curing agent is employed. Various polyamines can be used for this purpose, including aliphatic and aromatic amines, cycloaliphatic amines, a Lewis base or a Mannich base. For example, the aliphatic amine and cycloaliphatic amines may be alkylene diamines such as ethylene diamine, propylene diamine, 1,4-diaminobutane, .1,3-diaminopentane, 1,6-diaminohexane, 2,5-diamino-2,5-dimethylhexane, 2,2,4-trimethyl- 1 ,6-diaminohexane, 1, 11 -diaminoundecane, 1, 1 2-diaminododecane, 1,3- or 1,4-cyclohexame diamine, 1 -amino-3,3,5-trimethyl-5-amininomethyl-cyclohexane, 2,4- or 2,6-hexahydrotolvylene diamene 2,4xe2x80x2- or 4,4xe2x80x2-diaminodicyclohexyl methane, 3,3xe2x80x2-dialkyl-4,4xe2x80x2-diamino-dicyclohexyl methane isophoronediamine, trimethylhexamethylene diamine, triethylene diamine, piperazine-n-ethylamine, polyoxyalkylene diamines made from propylene oxide and/or ethylene oxide. Commercially available amine curing agents may sometimes include residual amounts of solvents such as benzyl alcohol used in the manufacture of the compounds. The aromatic polyamines may include 2,4- or 2,6-diaminotoluene and 2,4xe2x80x2- or 4,4xe2x80x2-diaminodiphenyl methane. Mixtures of amine curing agents may be employed. The amount of amine curing agent may vary depending on the amount of epoxy resin to be cured. In general, the amount of amine curing agent employed is so that the volumetric ratio of an amine side to an epoxy side is from about 30:70 to about 70:30, with a weight ratio of from about 1:15 to 15:1 being most typical. Typically, the mole ratio of amine curing agent to the epoxy resin is in the range from about 0.25 to about 2.5, and in one embodiment is about 1:1.